Mold is a common allergen that can grow in many locations inside or outside a dwelling. It can also be found thriving inside building cavities, between walls. Mold is a very common indoor contaminant, and a common cause of illness. Only a few dozen of the thousands of different types of mold are commonly found in dwellings for humans.
Molds reproduce by releasing spores into the air. The spores are extremely small, about 1 micron or about 0.00004 inches. Mold counts are often 1,000 times higher than pollen counts. Although tiny parts of the parent mold colony can break off and be inhaled, usually, inhaled microscopic spores are the source of health problems. A person's allergic response is a biological reaction to the protein in mold, so the reaction can occur whether the inhaled spores are dead or alive. A thriving mold colony often releases various gases, including volatile organic compounds, that are also a problem for sensitive individuals.
Different species of mold have different health effects ranging from mild symptoms to death in some individuals. Stachybotrys chartarum (Stachybotrys atra) mold is being studied for possible links to AIPH (Acute Idiopathic Pulmonary Hemorrhage) among infants. Some species of the mold Aspergillus can infect the entire body of a person, causing lung damage or other serious illnesses. Histoplasma capsulatum can affect the lungs, but can also be systemic. A mold colony can use any organic material for food, and can even derive nutrition from a layer of dust on non-organic surfaces.
Mold requires five ingredients to thrive: food, air, a surface to grow upon, suitable temperature, and moisture. In an occupied building, little can be done to eliminate the first four conditions. In these instances, only the manipulation of moisture can be used to eliminate a mold colony or to prevent a new colony from forming. In an unoccupied building, temperature and humidity may be managed to control the commencement or continuing growth of a mold colony.
Another factor in mold growth is a change in barometric pressure. Sporalation can be encouraged by a reduction in the barometric pressure. In nature, a storm front and the accompanying higher humidity levels and wet weather are normally preceded by a reduction in barometric pressure.
Mold growth is related to relative humidity. Relative humidity levels below about 70% will not support excessive mold growth. However, indicated relative humidity levels below 70% do not ensure safety. Although a house may have 60% relative humidity, microclimates of higher relative humidity may exist throughout the house, especially near cooler surfaces. This is because cold air cannot support as much water moisture as warm air. Thus, for a given amount of water vapor in the air, the cooler air will have a higher relative humidity.
For example, assume the air in a house has a relative humidity of 60% at 21° C. (70° F.). The air outside the house is 10° C. (50° F.), and the air between the outside wall and the inner drywall is at 16° C. (60° F.). Furthermore, the air in the house and the air between the walls can circulate, which is very common. In this case, the 16° C. air within the wall cavity will have a relative humidity of 70%, and may support excessive mold growth.
Temperature, humidity and barometric pressure measurement and control are mature and well-developed arts. Numerous temperature and humidity measuring, monitoring, and controlling devices have been developed. However, each of these devices has shortcomings making them inappropriate or ineffective for monitoring and controlling indoor environmental conditions that are conducive to mold and fungus growth conditions.
Some of these prior art devices measure rainfall and emphasize temperature measurements to determine the potential for mold growth. Other devices measure surface wetness, or condensed water vapor, to determine the potential for mold growth. These devices are of little use indoors.
Other devices measure temperature, relative humidity or barometric pressure, and will alert a user when a single predetermined parameter is observed. However, such existing devices are not capable of determining when a combination of two or more conditions is observed. For example, mold growth depends on a specific relationship between temperature and moisture. Neither a specific temperature or moisture value nor a range of temperature or moisture values will provide optimal conditions for mold growth. Both temperature and relative humidity must be compared to determine if conditions are satisfactory for mold or fungus growth.
Thus, there exists a need for a device that alerts a homeowner or dwelling occupant to the unobvious combination of environmental conditions that are conducive to unseen and destructive mold and fungus growth and assigns a threat level to the problem. There is also a need for a device that provides suggestions to reduce the threat of mold growth. There is a further need for an energy efficient control system that can automatically manage the temperature and humidity in multiple zones to eliminate the mold and fungus growth threat.
According to the present invention there is provided a device to monitor and measure temperature, humidity, and barometric pressure changes, and control temperature and humidity conditions. There is also provided an indicator to warn when environmental conditions are favorable for undesirable growth such as mold, mildew, and fungi. The present invention provides suggestions to the user to allow the informed user to take steps to reduce or eliminate the environmental conditions that are beneficial for such unwanted growth.
It is an object of the invention to provide an automatic system and method that can determine the most efficient way to eliminate the environmental conditions that are beneficial for such unwanted mold and fungus growth.
It is another object of the invention to provide an automatic system and method for mold and fungus growth inhibition that controls each environmental zone in a manner that causes the least change in the temperature of the environment zone and which uses a minimum of energy.